Since its first Food and Drug Administration (FDA) approval in 1998, deep brain stimulation (DBS) has gained significant popularity in the treatment of a variety of brain-controlled disorders, including movement disorders [3, 4]. The therapy of the DBS has significant applications in the treatment of tremor, rigidity, and drug induced side effects in patients with Parkinson's disease and essential tremor. Such treatment involves placement of a DBS electrode lead through a burr hole drilled in the patient's skull, and then applying appropriate stimulation signals through the electrode lead to the physiological target.
Usually, after the surgery of DBS implantation, the patient leaves the hospital with the stimulation system such as an internal pulse generator turned off, since transient lesional effects associated with microscopic brain edema caused by the surgery may interfere with DBS programming and lead to multiple adjustments in the parameter settings. The stimulation system is turned on typically about 1-5 weeks after the surgery is performed, for stimulation. This allows the patient to recover from the surgery and provides enough time for the transient lesional effects to resolve. The stimulation is accomplished by programmably applying appropriate stimulation signals to one or more electrode contacts of each implanted electrode. Thus, finding the optimal programming parameters so that it efficiently stimulates the target of interest is crucial to the DBS. Detailed principles and methods used to select the optimal programming parameters have been presented by different authors [1, 2].
Briefly, the first step in postoperative programming is the examination of the effectiveness and side effects induced by each individual contact. The electrode contacts are sequentially evaluated in a monopolar configuration in an effort to determine the contact that produces best compromise. Frequency and pulse width of the stimulation signals are typically kept at constant settings of about 130-180 Hz and about 60-120 μs, respectively. Amplitude is steadily increased to the tolerance level of the patient or until side effects occur. Repeating motor evaluation is then performed to assess the efficacy of stimulation. About ten to 15 minutes are allowed to pass between trials of separate contacts to allow the effects from previous stimulations to disappear. If a satisfactory result cannot be achieved with monopolar stimulation, more complex arrays including bipolar, tri-polar, quadric-polar, or multiple cathodes are tried. The initial programming session, as described above, can take several hours and requires continuous feedback from the patient to ascertain the degree benefits and to identify any side effects. This can be very taxing, especially when patients are kept off of medication for long periods of time. Furthermore, optimal programming may take several trials over many months to achieve, which can be frustrating to both patients and their attending health care professionals.
Automated selection of the optimal contact would facilitate the programming process and reduce the length of time required to determine optimum programming and thus be beneficial to the patients.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.